Self-locking carton



Sept. 13, 1966 G. E. PERRY 3,272,421

SELF-LOCKING CARTON Filed May 11, 1964 INVENTOR. GERALD E. PERRY FIG. 6MA M ATTORNEYS United States Patent 3,272,421 SELF-LOCKENG CARTON GeraldE. Perry, Waterville, Ohio, assignor to Owens- Illinois, Inc., acorporation of Ohio Filed May 11, 1964, Ser. No. 366,500 5 Claims. (Cl.229-39) This invention relates to improvements in self-locking bottomcartons.

More particularly, this invention relates to a carton whose bottom maybe easily set up [from one side without requiring access to the interiorthereof.

It has been the practice in the past, particularly in the case ofcartons which are intended to hold light material such as potato chipsheld in polyethylene bags, that the cartons are made of relatively lightcontainer boards and the erecting of the cartons, particularly thebottoms thereof, has necessitated folding the bottom into interlockingarrangement and then requiring the person erecting the box to reachinside and push the bottom outwardly to form the interlocked bottom.These cartons also required bottom closing flaps which necessarily havea width greater than one-half the width of the box. In other words, thebottom flaps require more board than the regular slotted container.

With the foregoing in mind, it is an object of this invention to providea collapsible carton having a self-locking bottom construction.

It is an additional object of this invention to provide a carton havinga self-locking bottom which requires no more boa-rd than a regularslotted container.

It is a further object of this invention to pro-wide a bottom structurefor a carton, IWheIeln the bottom of the carton may be formed byinwardly and downwardly folding hinged flaps into interlockingrelationship which upon release automatically form a planar bottomwithout requiring access to the inside thereof.

Other and further objects will be apparent from the followingdescription taken in conjunction with the annexed sheet of drawings,wherein:

FIG. 1 is a plan view of the blank from which the carton is formed;

FIGS. 2-5 are perspective views of the carton bottom construction of theinvention illustrating the sequence of folding to lform the self-lockingbottom; and,

FIG. 6 shows the top closing arrangement of the carton of the invention.

Referring to the drawings, the carton of the invention is composed oftour side wall panels 10, 11, 12 and 13 joined together in a tubularconfiguration by the usual manufacturers joint with a tab 14. The panels13 have downwardly extending flaps 15, 16-, 17 and 18 hingedly connectedthereto.

As can readily be seen when viewing FIG. 1, the flap is provided withtwo spaced-apart slots 19 and 20 formed in the lower free edge thereofwhich extend toward the panel 10 a predetermined distance. In a likemanner the flap 17 is provided with slots 21 and -22 which extendinwardly from the free edge of the panel a predetermined distance. Theflaps 16 and 18, which have substantially the same configuration, aregenerally comprised of trapezoidal-shaped portions 23 and 24 wvith thebase of the trapezoid portions being hingedly connected to the panels 11and 13 respectively. The flaps 16 and 18 also have integrally formedtherewith outer portions 25 and 26 which are of a predetermined widthand, as will be apparent from the following description relating to themanner of erecting the carton, should be of a width of approximatelytwice the length of the slots 19-22. The upper edge of the blank of FIG.1 is provided with a pair of flaps 27 and 28 and a pair of slotted flaps2 9 and 30. The flaps 27 and 28 are scored adjacent their outer edges,as will be apparent when viewing FIG. 6.

With particular reference to FIGS. 2-5, the manner of erecting thecarton bottom of the invention may be better understood. The two flaps15 and 17 are first folded inwardly into abutting coplanar relationship,as shown in 'FIG. 3. The flaps 16 and 18 are then folded inwardly intooverlying relationship 'with respect to the flaps v15 and 17 and byplacing the thumbs, for example, one on the flap 1'6 and one on the flap18, continued pressure will ttorce the flaps 16 and 118 and the flaps 15and 17 downwardly until the outer portions 25 and '26 of the flaps 16and 18 enter the openings formed by the slots 19-22, at which timepressure is released from the flaps 1-6 and 18 and the carton bottomautomatically squares itself into the configuration shown in FIG. 5.

The folding of the top of the carton, i.e., closing of the flaps 27, 28,29 and 30, is made after the contents have been placed within thecarton, at which time the flaps 29 and 30 are first folded inwardly andthe flaps 27 and 28, with their outer marginal scored areas, may then beinserted within the slots of the flaps 29 and 30 to form a complete,closed carton.

Thus it can be seen that the width W of the outer portions 25 and 26 ofthe flaps 16 and 18, in order to provide a closed bottom to the carton,must be sufiicient to substantially fill the space provided by the depthof the two slots 19 and 20 when the carton is folded. =In other words,the distance P; from the hinge to the end of the slot 20 and thedistance P from the hinge to the end of the slot 21 added together withthe width W ot the outer portion 25 of flap 16 should equal the width ofthe carton.

With respect to the trapezoidal-shaped portions 23 and 24 of the flaps16 and 18, it is only necessary that the height X of the trapezoidalportion be as great as the width Y of the fiaps 15 and 17. This isapparent from the standpoint that the flaps 16 and 18 necessarily foldover and have their end portions extend beneath the center part of theflaps 15 and 17 when in erected position.

It can readily be seen that by this construction, applicant has providedan easily erected self-locking bottom construction for a carton in whichit is not necessary to make the final squaring of the bottom from theinside, as is necessary in most presently constructed cartons of thistype.

While the intermediate portions of the flaps 15 and 17 appearsemi-circular in configuration, it should be readily recognized thatother configurations for this portion of the flaps 15 and 17 may beused. The principal reason for the semicircular configuration is topermit the outer portions 25 and 26 ot the flaps 16 and 18 to easilyenter the openings formed by the slots in the flaps 15 and 17, and uponrelease of the folding pressure or force, the flaps 16 and 18 will bearagainst the underneath of these portions of the flaps 15 and 17 quicklyand easily causing the squaring of the bottom of the carton.

It should be pointed out that the particular carton bottom constructionset forth above, uses no more board than a regular slotted containerbecause there is no overlapping of opposed flaps.

While the foregoing description has been directed to a self-lockingbottom construction for a tubular carton configuration, it should bepointed out that the particular flap closing and self-lockingarrangement Olf the invention could be easily applicable to the top of acarton, particularly in those cartons which are, in effect, loadedthrough the bottom. F or example, in the boxing of fruit, such asapples, it is common practice to carefully place the top layer of the.fruit in the carton when the carton is upsidedo wn. This is termedfacing the contents in the carton.

Various modifications may be resorted to Within the spirit and scope ofthe appended claims.

I claim:

'1. A carton having an integral, self-locking end closure comprisinifour foldably connected side panels forming a tubular configuration, afirst pair of flaps foldably con nected to the lower edge of opposedpanels of said tubular configuration, said first pair of flaps eachhaving a pair of spaced-apart slots formed in the free edge thereof,said slots continually increasing in width as they proceed from the endsthereof toward said free edge, said first pair of flaps adapted to befolded into coplanar relationship with the slots in one flap being inalignment with the slots in the other flap, a second pair of flapsfoldably connected to the lower edge of the other opposed panels of saidtubular configuration, said second pair of flaps having an outer portionthereof of approximately the same Width as the length of the slot formedby the closing of the first pair of flaps, said second flaps beingfolded into overlying relationship with said first pair of flaps andcontinued folding of said flaps forces the inward movement of said firstflaps until the ends of said second flaps enter the corresponding slotsin said first flaps and release of folding pressure on said second flapspermits the squaring of the flaps in interlocking relationship, and saidouter portion of said second flaps extending through the slots formed bysaid first flaps.

2. A carton in accordance with claim 1 wherein the edge portion of eachof said first pair of flaps between the spaced-apart slots therein is ofsemi-circular configuration.

3. A carton having an integrally, self-locking end closure comprising,four foldably connected side panels forming a tubular configuration, afirst pair of flaps foldably connected to the lower edge of opposedpanels of said tubular configuration, said first pair of flaps, eachhaving a pair of spaced-apart slots for-med in the free edge thereof,said first pair of flaps adapted to be folded into coplanar relationshipwith the slots in one flap being in alignment with the slots in theother flap, a second pair of flaps folda'bly connected to the lower edgeof the other opposed panels of said tubular configuration, said secondpair of flaps having a centrally-located, rectangularlyshaped outerportion thereof of approximately the same width as the length of theslot formed by the closing of the first pair of flaps, the width of saidouter portion being substantial and substantially less than the width ofthe lower edge of the side panel to which said flap is foldablyconnected, said second flaps being folded into overlying relationshipwith said first pair of flaps whereby continued folding of said secondflaps forces the inward movement of said first flaps until the outerportions of said second flaps enter the corresponding slots in saidfirst fiaps and release folding pressure of said second flaps permitsthe squaring of the flaps in interlocking relationship, said outerportions of said second flaps extending through the slots formed by saidfirst flaps.

4. A carton in accordance with claim 3 wherein each of the slots in saidfirst pair of flaps increases in width as it proceeds from the endthereof to the free edge of the flap.

5. A carton in accordance with claim 4 wherein the edge portion of eachof said first pair of flaps between the spaced-apart slots therein isOlf semi-circular configuration.

References Cited by the Examiner UNITED STATES PATENTS 241,409 5/1881Osborn. 2,030,295 2/1936 Hodge 22939 X 2,053,857 9/1936 -Weiss 22939 X2,541,644 10/1948 Wood 22939 X 2,794,544 6/1957 Firth 22939 X 3,062,42611/ 1962 Mason. 3,178,096 4/1965 Reeves et al. 229-39 JOSEPH R.LEC-LAIR, Primary Examiner.

D. T. MOORHEAD, Assistant Examiner.

1. A CARTON HAVING AN INTEGRAL, SELF-LOCKING END CLOSURE COMPRISING,FOUR FOLDABLY CONNECTED SIDE PANELS FORMING A TUBULAR CONFIGURATION, AFIRST PAIR OF FLAPS FOLDABLY CONNECTED TO THE LOWER EDGE OF OPPOSEDPANELS OF SAID TUBULAR CONFIGURATION, SAID FIRST PAIR OF FLAPS EACHHAVING A PAIR OF SPACED-APART SLOTS FORMED IN THE FREE EDGE THEREOF,SAID SLOTS CONTINUALLY INCREASING IN WIDTH AS THEY PROCEED FROM THE ENDSTHEREOF TOWARD SAID FREE EDGE, SAID FIRST PAIR OF FLAPS ADAPTED TO BEFOLDED INTO COPLANAR RELATIONSHIP WITH THE SLOTS IN ONE FLAP BEING INALIGNMENT WITH THE SLOTS IN THE OTHER FLAP, A SECOND PAIR OF FLAPSFOLDABLY CONNECTED TO THE LOWER EDGE OF THE OTHER OPPOSED PANELS OF SAIDTUBULAR CONFIGURATION, SAID SECOND PAIR OF FLAPS HAVING AN OUTER PORTIONTHEREOF OF APPROXIMATELY THE SAME WIDTH AS THE LENGTH OF THE SLOT FORMEDBY THE CLOSING OF THE FIRST PAIR OF FLAPS, SAID SECOND FLAPS BEINGFOLDED INTO OVERLYING RELATIONSHIP WITH SAID FIRST PAIR OF FLAPS ANDCONTINUED FOLDING OF SAID FLAPS FORCES THE INWARD MOVEMENT OF SAID FIRSTFLAPS UNTIL THE ENDS OF SAID SECOND FLAPS ENTER THE CORRESPONDING SLOTSIN SAID FIRST FLAPS AND RELEASE OF FOLDING PRESSURE ON SAID SECOND FLAPSPERMITS THE SQUARING OF THE FLAPS IN INTERLOCKING RELATIONSHIP, AND SAIDOUTER PORTION OF SAID SECOND FLAPS EXTENDING THROUGH THE SLOTS FORMED BYSAID FIRST FLAPS.